1,2-Dichloroethane → (R)-2-((S)-2-benzyloxycarbonylamino-3-hydroxy-propionylamino)-propionic acid methyl ester

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Reaction Steps

Diisopropylethylamine (375 mL) was added dropwise to a cooled mixture of (R)-2-amino-propionic acid methyl ester hydrochloride (100 g, 0.716 mol), EDC (165 g, 0.86 mol), carbobenzyloxy-L-serine (171.4 g, 0.716 mol) and DCM (3.6 L). The resulting mixture was stirred under nitrogen at ambient temperature for 16 h. After removing solvent in vacuo at 40° C., the residue was diluted with saturated sodium carbonate (1 L), water (1 L) and extracted with EtOAc (2 L, 2×1 L). The combined organic phases were washed with 2 M hydrochloric acid (1 L), saturated brine solution (1 L), dried over magnesium sulfate and concentrated in vacuo at 40° C., to give the title compound (172 g) as a colourless solid. 1H NMR (Me-d3-OD): 7.44-7.28 (6H, m), 5.13 (2H, s), 4.46 (1H, d), 4.43 (1H, d), 4.25 (1H, t), 3.82-3.68 (5H, m), 1.39 (3H, d).

Provenance & Evidence